Hydrogen migration under thermal stress gradient in zirconium alloys results in formation of
hydride blisters [1]. An array of blisters makes Zirconium alloy components of nuclear
reactors susceptible to fracture [2]. The whole process of hydride blister formation and
fracture of these components is very complex and involves hydrogen migration under thermal
gradient, hydride precipitation, straining of the matrix, setting up of hydrostatic stress
gradient, enhanced hydrogen migration under the combined influence of thermal and stress
gradient, stress-reorientation of hydrides [3], cracking of hydrides, crack growth by delayed
hydride cracking mechanism [4], interlinking of blisters and spontaneous fracture of the
component.
In this work we estimate the stress components in hydride blisters and the surrounding matrix
for certain assumed blister depths. The estimated stress predicts the hydride orientation in the
matrix surrounding the blisters and will be subsequently used to model the hydrogen diffusion
under hydrostatic stress and temperature gradients.